hi tom,
you could connect the TTL signal to the SMA connector
on the adc board, called "sync in".
this is a spare digital input, 0 to 2.5 volts, 50 ohm.
but it would be easier to connect your signal to a printer port on your
computer,
or buy an inexpensive digital input to USB board. then you
wouldn't have to modify the fpga code; your computer could read the
status bit directly.
best wishes,
dan
Henry Chen wrote:
Hi Tom,
Any one of the IBOB's header GPIOs should be able monitor it. You
will probably need to put in a series resistor to protect the
LVCMOS inputs pad from the TTL signal:
http://www.xilinx.com/support/answers/10835.htm
Thanks,
Henry
On 2/23/2011 12:12 PM, Tom Kuiper wrote:
We have a box with an iADC, an iBOB and an 800 MHz clock, plus power
supplies, for our SETI spectrometer. The clock is (supposedly)
locked to a 100 MHz reference. There is a TTL lock indicator we
would like to monitor. Can we feed that signal onto some appropriate
pin of the iBOB and read its state?
Thanks and regards
Tom
